The subject invention relates to an adjustable finishing insert assembly for use with a milling cutter. More particularly, an improved assembly is disclosed which facilitates the adjustment of the angle of a finishing insert relative to a milling cutter to improve the finish of the workpiece.
In the production of a metal article, a variety of machining techniques are used. One prior art technique utilizes a rotatable milling cutter for machining the desired configuration in a piece of metal. The equipment for a milling operation includes a generally cylindrical milling cutter having a planar cutting surface. A plurality of indexable cutting inserts, formed from wafers of hard cutting material, are disposed about the periphery of the cutter, adjacent the cutting surface. The milling cutter is adapted to be rotated about its longitudinal axis by a powered spindle.
In a typical machining operation, the milling cutter is rotated at high speed and a workpiece is moved past the cutter on a motorized feed table. The assembly is adjusted such that as the workpiece is moved past the cutter, a relatively thin layer of metal will be machined off the piece.
In many milling operations, especially those utilizing high volume, special purpose machines, the milling cutter is tilted relative to the workpiece such that the tail end of the cutter is spaced away from the workpiece. The tilting or heeling of the cutter is necessary to prevent those portions of the workpiece already machined by the front end of the cutter, from being scratched or otherwise damaged by the inserts on the tail end of the cutter.
The requirement of tilting the cutter to prevent damage to workpieces unfortunately gives rise to another problem. More specifically, in order to machine a smooth finished cut, it is necessary to address a flat cutting edge of an insert parallel to the workpiece. As can be appreciated, when the cutter is tilted, the angle of the cutting edges of the fixedly mounted inserts are canted relative to the workpiece, such that a scalloped or saw-toothed surface profile is generated.
Various methods have been devised to negate the saw-toothing effect created by the spindle tilt. For example, the insert pockets can be initially manufactured to compensate for a specific spindle tilt. However, this method is undesirable since the latter type of cutter can only be successfully used in a machining operation where the specifically designed tilt is suitable. Another method which has been utilized includes the provision of a finishing insert having an elliptically shaped cutting edge. In theory, as the spindle tilt of the cutter is changed, a different portion of the elliptical cutting edge of the finishing insert comes into contact with the workpiece. This method has been successful in reducing the scalloped effect on the workpiece. However, in some applications, even minor surface imperfections are unacceptable and it becomes necessary to address a flat cutting edge of an insert parallel to the workpiece.
Accordingly, it is an object of the subject invention to provide a new and improved milling cutter having a finishing insert which can be readily adjusted to compensate for the effects of spindle tilt.
It is another object of the subject invention to provide a new and improved milling cutter having a unique finishing insert assembly which can be readily adjusted to vary the angle of the finishing insert relative to the milling cutter to improve the finish on the workpiece.
It is a further object of the subject invention to provide a milling cutter having a new and improved adjustable finishing insert assembly which can be readily adjusted to insure that a flat cutting edge of the finishing insert is properly addressed to the workpiece thereby insuring a smooth surfaced profile.